From his election in 1572 to his death in 1585, Pope Gregory XIII schooled in the upheavals in the Catholic Church that marked the preceding violent decades, spent a great deal of money on the building and restoration of Rome's streets, churches and public monuments. One major, unknown and unstudied monument, the three-story apartment rising up from the Vatican Palace called the Tower of the Winds, was built and painted to celebrate the most famous achievement of Gregory's papacy, the calendar reform. The program of the entire tower proclaimed with assurance not only Gregory's political and religious authority over the capital, but also Gregory's domination of nature, time, and past and present cultures. Its innovations in architecture and decoration, efflorescent Flemish landscapes in all of its seven rooms and its wider religious and political purpose in the culture of Gregorian Rome and the Counter-Reformation, are all subjects of the book.